numpy.expm1() in Python (original) (raw)

Last Updated : 29 Nov, 2018

numpy.expm1(array, out = None, where = True, casting = 'same_kind', order = 'K', dtype = None) : This mathematical function helps user to calculate exponential of all the elements subtracting 1 from all the input array elements. Parameters :

array : [array_like]Input array or object whose elements, we need to test. out : [ndarray, optional]Output array with same dimensions as Input array, placed with result. **kwargs : allows you to pass keyword variable length of argument to a function. It is used when we want to handle named argument in a function. where : [array_like, optional]True value means to calculate the universal functions(ufunc) at that position, False value means to leave the value in the output alone.

Return :

An array with exponential(all elements of input array) - 1.

Code 1 : Working

Python `

Python program explaining

expm1() function

import numpy as np

in_array = [1, 3, 5] print ("Input array : \n", in_array)

exp_values = np.exp(in_array) print ("\nExponential value of array element : " "\n", exp_values)

expm1_values = np.expm1(in_array) print ("\n(Exponential value of array element) - (1) " ": \n", expm1_values)

`

Output :

Input array : [1, 3, 5]

Exponential value of array element : [ 2.71828183 20.08553692 148.4131591 ]

(Exponential value of array element) - (1) : [ 1.71828183 19.08553692 147.4131591 ]

Code 2 : Graphical representation

Python `

Python program showing

Graphical representation of

expm1() function

import numpy as np import matplotlib.pyplot as plt

in_array = [1, 1.2, 1.4, 1.6, 1.8, 2] out_array = np.expm1(in_array)

print("out_array : ", out_array)

y = [1, 1.2, 1.4, 1.6, 1.8, 2] plt.plot(in_array, y, color = 'blue', marker = "*")

red for numpy.expm1()

plt.plot(out_array, y, color = 'red', marker = "o") plt.title("numpy.expm1()") plt.xlabel("X") plt.ylabel("Y") plt.show()

`

Output : out_array : [ 1.71828183 2.32011692 3.05519997 3.95303242 5.04964746 6.3890561 ] References : https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.expm1.html#numpy.expm1.